Fluid meter



H. E. HARTIG oct. 1, 1935.

FLUID METER Filed March 11,k 19:52

4 Sheets-Sheet 1 i, Ns ETT 9, u w 3W 0, H 2 m D,

e m uf/ 4 e HM G m., M IR, mmv. AMh HDm @ma la EwM HFM u Oct. l, 1935. H. E. HARTIG FLUID METER Filedv March 11, ,1932

.; Hemg E. I'lortig.

4 Sheets-Sheet 3 aomirv H. E. HARTIG Oct. l, 1935.

FLUID METER Filed March 11, 1932 4 Sheets-Sheet Patented Oct. l, 19.35

Henry E. Huug, RobbinsaolJMino., mignon of one-half to Hugh B.Wilcox, Minneapolis,

l Application Moron 11, 1932, serai No. 598,208

' lza claim. (ci. '1s-167') My invention relates to iluid meters and has for an object to provide a method of measuring the flow of iiuids and a meter by means of which the method may be carried out whereby great o accuracy maybe procured.

Another object ofthe invention resides in providing a meter in which vibrations oi' knownl irequency are set up in the fluid whose velocity is to be measured, and in which the velocity of the iiuid is computed from the change of wave length of the vibrations caused by the flow oi' the iluid.

An object of the invention resides in providing a iiuid meter in which two vibrations are set up in the iuid and in which the phase relation of the vibrations is adjusted to` produce predetermined vibration conditions.-

Astill further object ofmy invention resides. in providing a meter in which undesirable reected sound waves are eliminated,

Another object of the invention resides in the method ot measuring the ilow of fluids which consists in setting up vibrations in the iluid and 1 in setting up other vibrations adapted yto completely destroy the vibrationsvilrst set up except in that part of the pipe in which the measurements are conducted whereby the possibility oi disturbing reflected waves from external reflect-` ing surfaces is eliminated.

An object of the invention resides in providing a meter which operates at a nxed frequency.

A feature of the invention resides in providing a device which does not require calibration, but which determines fluid velocity directly through linear measurement and the measurement of the frequency of the vibrations employed.

An object of the invention resides in providing a meter in which the vibrations in the iluid emanating from a single source are set up at two localities therein and in which the lengths of-v the paths of travel from the source to such localities are adjusted so that destructive interfer- 'ence between the vibrations in the uid may be produced.

Other objects ot the invention reside in the novel combination and arrangement of parts and in the details of constructionhereinafter illustrated and/or described.

In the drawings: Y

Fig. 1 is a longitudinal, section, elevational view taken through a pipe through which the iluid to be measured travels and illustrating an embodiment of my invention appliedV thereto with portions of the invention shown diagrammatically.l

Fig. 2 is a fragmentary elevational view of a f portion of the structure shown in Fig. 1A illusline L-l oi' Fig. 2.

trating the scales and sleeve construction together with the adjusting devicev therefor, said view being drawn to a larger scale than Fig. 1. Fig. 3 is a similar fragmentary elevational view of another portion of the invention drawn to the 5 same scale as Fig. 2.

Fig. 4 is an elevational sectional 'view taken on Fig. 5 is a plan view of the electric generator used in the invention with a portion of the cover 10 thereof removed.

' Fig. 6 is a wiring diagram oi' the ampliiler of the invention.

Fig. 7 is a sectional view of the vibration producing device of the invention. I 15 Fig. 8 is a sectional view of one oi the vibration transmitters of the invention.

Fig. 9 is a view similar to Fig. 1 illustrating a modification of the invention.

Fig. 10 is a wiring diagram oi' one of the phase 20 Shifters used with the form of the invention shown in Fig. 9.

Fig. 11 isAv a view similar to Fig. 1 showing a simplified vform of the invention for illustrating 25 the theory oi operation zthereof.

For the purpose of more readily explaining the theory or operation' and the method employed with my improved'meter, I have shown diagrammatically in Fig. 11, a simplified or skeleton form of my invention, parts of which are identical with 30 other parts of the device shown in Fig. 1. It has been assumed that the fluid, .whose velocity is to be measured, ilows through a pipe Ill in the direction indicated by the arrow. This pipe may be partl of the system through which the 35 fluid passes or may -be especial section oi'pipe inserted into the system and containing the various parts constituting my invention. This pipe is of relatively great length as compared to its diameter and may be connected to the system o l in any suitable manner as by ilanged iittings, not shown in the drawings or otherwise.

The method employed in my invention consists in generating vibrations in the pipe I0, which are ailected by the travel oi' the iluid through 45 the pipe to change the wave length of said vibrations. 'I'he difference between the wave lengths of the vibrations measured at certain localities in the pipe in opposite directions with respect to the source or vibration is utilized to determine 50 the actual velocity of the uid in the pipe. For this purpose, two vibration transmitters I l and I2 are employed which communicate with the interior of the pipe l0 at two definite localities along the length thereof which I have designated 55 designed for generating alternating electric g current, which vis accomplished Vby varyingv the surface of base 38 so that the same may vibrate- 28; 29;.'and 30 to a selector 3|.

and I6 with an electric transformer I1, which in turn is connected through conductors' |8 and I9 with an electric` generator 20, generating -an alternating electric current of fixed frequency.

Within the pipe l0 and in advance of the vibration transmitter I2 is situated a vibration detector 2|.` Following the vibration transmitter II is situated a similar vibration detector 22, these detectors being situated at localities ,along the pipe designated as stations C and D and located distances b from thestations A and B. vThese distances may be equal tothe distancea or less than the same as desired... The detectors 2| and 22v are connected through tubes 23 and 24 to `two electric pick-up' devices 25 and 26, which in turn are connected throughconductors 21, The selector 3| is in the nature of a dou'ble pole double throw switch'which lis connected through' conductors 32.and. 33 with an audion amplifier 34. v`The amplifier 34 is connected through conductors 35 and 36 witha head phone or telephone receiver 31 or any other similar sound producing device such as a loud speaker or the like. The g various parts used inthe form ofthe invention shown in Fig. 9 above referred to will nowbe describedindetail. Y

Any type of electric generator maybe used. An electric generator20 well known in the, art is illustrated in .detai-l in'Flg. 5. This generator strength of a direct current at -predetermined regular intervals.

and which is'formed aboutv the outer margin thereof with a groove 39 for the reception of a -cover 4|! enclosing the entire mechanism ofthe same. The generator 20 includes a vibrator 4|, which may be a tuning fork or similar device constructed with two prongs-42' and 43. and a shank 44 connected thereto. 2r This .vibrator is mounted upon the base 38 through a strap 45 which `envelopes the shank 44 and which is secured to said base through a number of screws is so mounted that the 46. The vibrator 4| prongs 42 and 43 thereof extend above the upper freely when set in motion.' Between the two prongs 42 and '43 of vibrato 4| is disposed an electromagnet 41 which isattached to the base 38 by means of a strap 46,

said strap being secured to-the base-through screws 49. fl'iiselectromagnet has poleV piecesand 5| at opposite ends thereof which are.

equally spaced from the prongs 42 and 43 of vibratorv`4| and which operate to attract said prongs when the coil of Y said electromagnet is energized 4and which release the prongs when the current through the coils is interrupted or weakened. Attached to the-base 38 of generator 20 -is a current controlling device 52 Afor varying or interrupting the current. This device oper# atesv on the principle of a microphone land consists of a case 53 formed with legs 54 whereby This device includes. a base. 38.l which is constructed of insulating material the. same may be attached through screws Il to the base 36. The case 53 is constructed with a cavity adapted to be filled with carbon particles indicated at 56. The case 53 is closed and the carbon particles retained within the same A 5 through a thin vibrating diaphragm I1 which is clamped in -position on .said case through 'a threaded collar 58. 'I'he diaphragm 51 ispref- .erably constructed of mica or some other suitable insulating material andhasattachd toit 10 at its center a stud or short bolt 59'.V which in turn is attached to the prong 43 of vibrator 4|.

This bolt extendsv directly through'said prong and is threaded as indicated at 63 to receive two Vnuts 6| and62, by means of which the dia- 15 phragm 51 may b e adjusted with respect to the prong 43. 'As the 'prong 43 vibrates. a vibration is set up in the diaphragm 51 compressing and expanding-.the vcarbon, particlesv56 within case 53. This reduces and increases the resistance 20 of the said carbon particles so that-current flowing through the screw and case '54 is caused to pulsate, `varying in intensityr in accordance withthe pressure applied tothe carbon particles 56. 25 yThe generator 20 utilizes a battery 63 or any other suitable Y. source of direct current, `which has connected toit two'fconductors' 64 and 65. The conductor 64 is connected to the strap 45 which is in electrical;contactwithfvibrator 4|, 30';

while the conductor 65 is connected to one sideV of the coil lof the electromagnet 41. 'I'he other side ofthe coil of-this electromagnet'is connected to the conductor I8 while cmductor I9 is connected to the case device52. Y y.

lThe operationV of the'generator '2611s as follows:l When the circuit through the battery 63 is closed as by a suitable switch'l 66, current ows from conductor through strap 45, vibrator' 4I, 10 prong 43 thereof, bolt 59,' the carbon particles 66, case 53, conductor I9, transformer I1, conductor- 1| 3, the coil of electromagnet 41 and through conductor 65 back tothe battery. This causes the electromagnet 41 to become energized 45 which attracts the two prongs 42 and 43.' Move-i` Yment of the prong 43 relieves the pressure uponA the carbon particles 56 which reduces the `current passing through the same and `through `the coil of the electromagnet. This reduces the 50 magnetic force acting on the prongs' 42 and 43vv which causes a movement ofv the same.- As soon as the electromagnetic action on these prongs is reduced, the pressure is again increased' on Vthe carbon particles and the cur- 55 rent increases. Thesteps are then` repeated. In this manner,v the two prongs 42 and 43 are set into vibrationand pulsating current produced in the transformer I1. Due to thefact that ay vibrator inthe nature'of a Vtuning fork has its 60 i own period of vibration, the frequency of the pulsations of the current produced are extremely regular and may be accurately determined. Furthermore the frequency of the pulsations with such type of device are not altered by minor 65 changes in thev voltage or condition of the battery 63 so that as long as, the device operates,

. the same can be relied on toproduce a pulsating current of predetermined regular frequency. The vibration producing device |4 may consist 70 of an ordinaryr telephone yor radio receiver or phone,fwhich is adapted to set up vibrations in the air adjoining the diaphragm thereof when the same is energized through a pulsating or alternating current. One such device is shown in4 75 5I ofthecurrent controlli!!! 35 itl Fig. '1, said device being identical. in all of the forms of the invention. This device "comprisesa case 66 preferably constructed of insulating material which has mounted in it a magneticallyelectromagnet. The tube structure I3, previousv ly referred to, is formed with three branches II9, |20, and |2I, which are secured together in any suitable manner. 'Ihe branch ||9 is attached to Vthe vibration producing device I4 and is formedk with an outwardly extending flange 14 of substantially the same diameter as the diaphragm 69. 'Ihis flange is disposed adjacent the .diaphragm 69 and is separated therefrom through a washer 15, said flange being clamped together with the diaphragm 60 to the, case 66 through the threaded collar 10. The vibrations set up by the diaphragm 69 are transmitted tothe air within the branches H9, |20, and |2| of the tube structure |3, where the same are utilized to produce the effects desired as will be presently described in.

detail.

Any form of vibration transmitter capable of transmitting the vibrations imparted to the air within the tube structure I3 to the4 uid in the pipe may be utilized. One device of this character isshown as a Brocca tube. Such vibration transmitter is shown -in detail in Fig. 8. This vibration transmitter comprises a fitting 16 which is threaded at 11 to screw into the pipe I9 at the required locality. Thistting is cOnstructed at its outer end with a tube connection 18 which is adapted to receive the particular tube to beconnectedtherewith. The fitting 16 terminates at its other end in4 a short neck 80 which extends inwardly into the pipe |0. This neck has mounted upon it a nipple 8| which is globular in form vand which nts tightly over the neck 80. Where the pressure of the fluid is not greatly in excess of atmospheric pressure, the nipple 8| may be constructed of rubber or some other suitable flexible material. Where the pressure is suiilciently great, the nipple 8| may be constructed of metal or'any other suitable material capable of transmitting vibrations to the `fluid within the pipe |0.\ The fitting 16 is constructed with aglio? 82 which communicates with the interior of th l nipple -0| and with the tube connected to said tting.

The tube structure I3 as previously described,

comprises three branches |I9, |20, and |2I, theVA branch I|9 being connected tothe vibration producing device I4; The branch |20 includes a short tube 12 which is connected to tube 1| and to a valve 63. This branch further includes a bent tube 19 which is connected to the detector II through the tube connection l18 thereof.

^ The branch I2| of tube structurev I3 includes a tube 13 which is enlarged at its outer end as indicated at 86 to form a longitudinal bore 81 in which another tube 88 is slidnble. The tube 88 is connected to a hose 85 which in turn is connected to a short tube 84 issuing outwardly from the tting 16 of transmitter I2. By means of this construction, the length of the paths throughy the tube structure for the transmission of the vibra# tions produced by the vibration vproducing device I0 can be varied in a manner and for a purpose` to be presently described in detail.

The two vibration detectors 2| and 22 may be .of any suitable type. VVIf desired, these devices\ mayv be constructed the same as the vibration transmitters and` I2 and function in an inverse manner receiving vibrations from the fluid whose velocityis to be measured and setting up vibrations in the air within the tubes 23 and 24 connected to the'electric pickup devices 25 and 26. The pickup devices 25 and'26 are in the nature of telephone receivers and as shown in Fig. 7

' and previously described. As vibrations are set `10 u'p in the air in tub 23 and 24, the diaphragm of these devices vibrate, causing the flow of pulsating currents in the circuits 21--28 and 29-20. When these conductors are connected to the `amplifier 34 throughthe selector 3|, the sounds 15 produced by the vibrations set up in the pipe |0 may be heard in the receiver 31. Although I have referred to the pickup devices 25 and 26 as being vin the nature of telephone receivers yet it can readily be comprehended that a telephone micro- 20 phone may be employed. The amplifier 34 is preferably of the well known audion type and a wiring diagram for such an amplifier vis shown in detail in Fig. 6. 'I'his amplier consists of one or more audion tubes 89 25 and 90 which are formed with laments 9|, grids 92, and plates 93. A conductor 90 is connected 1 y toboth of the filaments 9| of tubes 89 and 90 and is further connected to a switch 95. This switch, n in Vturn is connected toan A-battery 96 which 3o is further connected to a conductor 91, leading back to both of the filaments .9| of said tubes. When switch is closed, both of the filaments of the tubes are energized and the tubes function in the usual manner.

'Ine two conductors 32 and 33, previously referrcd to, 'which receive the input for the amplifier arevconnected in a tuned circuit including a variable condenser 90 and the primary 99 of a transformer |00.- Conductors 32 and 33 are 40 directly connected to said condenser and primary, the same being' in parallel with respect to one another. The secondary I0| of thel transformer I 00 is connected through a conductor |02 to the grid 92 of tube 89, whilethe other side of said 45 secondary is connected through a conductor |03 withthe conductor 94 leading to the filaments of the tubes.. The plate 93 of tube 89 is connected through a conductor |04 with the primary |05 of another transformer I 06. Primary |05 is further 50 connected to a conductor |01, which is connected with the positive side of a B battery |06. This B battery is in turn connected to the conductor 91 through a conductor |09, which as previously brought out is connected to the laments 9| of 55 the two tubes. 'I'he secondary ||0 of the transformer |06 is connected through a conductor I|| with the grid 92 of tube 90 while the other side of the secondary of this transformer is connected through a conductor ||2 with the conductor 94 60 leading to the A battery 96. The outputfrom the tube 90 passes through a tuned circuit including a transformer H3 provlded with a primary |I4 and a secondary ||5 and a variable condenser 0. The plate 93 of tube 90 is connected through 65 a conductor I II tions set up by the vibration producing device I4, 75

I Vwhich as previously described, was actuated through the generator 20 of'electrical pulsating current. When properly tuned, weak vibrations set up in the pipe I are amplified so that the same may be readily heard in the receiver or phone 31 when the amplifier is connected to either of the electric pick-up devices 25 or 28. g

In using the meter the fluid whose velocity is to be measured is brought to rest within the pipe ill. The tube 88 is next adjusted with respect to the portion 88 of tube 1l so that the sound procured, when the selector is connected to either stations C or D, is a minimum at both of these stations. The relation of the tube 88 andsleeve BG-.is thennoted and reference marks made on the same. This position of the parts of the tube structure will hereinafter be referred to as the normal position of the tube structure. The fluid whose velocity is to be measured is then 'causedto flow through pipe. I0 and the selector 'Il shifted to connect thepickup device 2i operating with detector 22 to the Vamplifier 3l. Tube I8 is next adjusted relative to portion Il of tube 13 so that` soimd in phones Il is again a minimum. The relative movement of the parts of the tube structure from normal position is then measured. Selector 3| is then shifted to its other position so that the pickup device .2l is connected to the amplifier and the procedure repeated. The relative movey ment of the parts from normal position is again measured. After these measurements have been taken the frequency of the generator 2l is determined, and from this data the velocity of flow of the fluid may be calculated. .f

Before going into the method of computing the velocity of flow of the fluid-I it has, been thought to be of advantage 'to explain the theory of operation and tov-state the. assumption on which the theory is based. This can best be compre-- hended by referencepto'llig. 1l.l The pipe III is assumed to be smooth upon the interior thereof and free from obstructionsv which might cause a reflection of the vibrationsset vup in the nuid passing through the same.- The said pipe. as stated. has been assumed to be of sumclently great length so that the reflections from the ends of the pipe would be dissipated before the same might return to the meter proper. The frequencyl of the electricugenerator 2l is preferably such that a fairly long wave length results and for the sake of illustration, the frequency selected has been assumed to be such as to produce three whole wave lengths between the two stations A and B, the fluid being at rest. The branch ll of tube i3 is located at a locality such that the paths oftravel of the vibration set-up in the two branches of said tube are ci' different lengths and so that the difference in length is approximately equal to one-half a wave length. It will be readily comprehcnded that when the generator 20 is set into operation, the vibration producing device i4 sets up vibrations in the -air column within branch I I9 of tube structure I3 which travel .through the branches |20 and |2| of said tube structure. The

the pipe i0.- Assuming the iiuid to be at rest, the curve |22 (Fig. 11) would represent the vibra- 'tion -set up at station B and tlnicurve |23 represent the vibration set up at station A.' The waves produced at these stations would hence be a'ut of phase due to the fact that the paths through which the vibrations are transmitted are of different length. If the difference in the length of \number. Such number might be indicated by 7s' the path through branches |20 and |2| were exactly equal to one-half a wave length and the' intensity of waves |23 is adjusted to equal that of wave .|22 by means of valve 8l there would be destructive interference between the two waves,

and no disturbance would be present at either stations C or D yof the meter. In such case by y placing the amplifier 34 and phone 31 in operation and by connecting the same to either of the electric pickup devices 25 or 26' throughv the selector 3|, no sound would be heard in the phones at either station C or D during a continuance of such conditions. If, however. the fluid were flowi Qing in the direction indicated bythe arrow, the4 velocity of travel of the vibration set up in the fluid by the vibration producing device Il would be affected by the velocity of the uid and complete destructive interference would not result.4

A sound could then be'heard in the phone 31. If, in such'case the tube 8 8 were slid along the bore Il of the portionr I8 of tube 1 3, the length of the path of the vibrations inbranch |2l could be altered and by proper adjustment. complete destructive interference again produced at either of the stations C or D. Due to the fact that the wave length of the lvibrations originated at the transmitter I2 is increased by the now of the fluid and the wave length of Athe vibrations produced at the transmitterli decreased with the fluid flowing as shown, complete destructive interference could not be produced at both stations C and D with one setting of the tube Il and tube 1I, but would require two settings, in each case representing increases in the length of the normal path of Y the iluid through this branch of the tube struc' ture.. By'measurins. the movement of the tube I8 with respect tothe sleeve Il as previously described and through knowledge of the frequency oi.' the generator, the exact velocity of the fluid without calibration of thev meter as follows:

For the purpose of calculation let V be the Avelocity of propagation of the vibrations in the pipe I0 when the fluid therein contained is at rest; Also letl!l be the frequency of the pulsating `current generated -by the generator 2l and consequently the frequency of the vibrations set .up by the vibration producing device Il and inthe pipe 2l can be mathematically determined transmitted to the fluid in the pipe Il through 6o transmitters li and I2. Then l 7,1 l F will be the wave length of a vibration having the frequency F. If we now let N be the number of wavelengths in the distance a between stations A and B, then a would equal a For thesake of illustration, the distance a has been assumed to be equal to a whole number of wave lengths which as previously stated, has been chosen as three.

Ifthe fluidin pipe It isassumedtobeinuniform motion from right lto left as indicated by the arrow in Flg..11 with a velocity o, the velocity of propagation oi' thevibrations in the :duid in l pipe ill from right to left would be V+v. Since the wavelength in such case would be greater than when the uidwas at rest, the number of wave lengthsin the distance a between stations A and B would no longer be N, but a smaller N-Ki where Ki represents a fractional part of the new wave length,

V-l-v In such case, the distance a would be equal to assuming that the path through branch |20 of tube structure I3 remained fixed. It would then become necessary in order to obtain destructive. interference at C to decrease the path through branch 2| by the same fractional part of a wave length, namely K1. This would be effected by telescoping the tube with .respect to the portion 85 of tube 13 a distance which' might/ be designated by the reference character Si. This adjustment, however, would not give rise to maximum destructive interference at D since the velocity of propagation of thevibrations from left to right would be V-v. Since the wave length from left to right would be smaller than when the iiuid was at rest, the number of wave lengths in distance a would be larger than -N and might be represented by the symbols N --Kz where K2 represented a fractional part of the new wave length inconduit I0. In such case, the distance a would be equalto To .obtain maximum destructive interference at D it would be necessaryto lengthen the path through branch |29 by the same fractional part of a wave length, namely Kn. This would again be effected by telescoping said branch and lengthening it over its normal position an amount referred to by the reference character Si.

If W, be considered the wave length in the tube structure 3, then K: and K1 may be computed from the wave length and the distances representing the adjustment of the tube structure |3 in accordance with the following formula:

and

By solving the two simultaneous equations previously referred to defining the distance a in terms N, K, V, and F and by eliminating V from these equations, the velocity of the fluid in the pipe can be obtained which is repreesnted in the following equation:

f v= aos K2) In some practical cases, a straight pipe of sufiicent length to dissipate the vibrations which might be reflected from irregularities in the pipe structure and the ends of the pipe or bends therein cannot readily be procured, I hence found it s l s desirable to develop the device shown-in Fig. l. which makes it possible to determine accurately the rate of f|ow in the pipe regardless of the form or construction thereof, except in the length of the pipe in which the apparatus is installed.

The method by means of which this is made possible consists in setting up the vibrations at four stations in the pipe in such a manner that when the various tubes are properly adjusted, all of the vibrations in the pipe are eliminated except in the length of pipe in which the meter is installed. 'I'here being no vibrations in the external portions of the pipe there can be no reflected vibrations to interfere with the proper ydetermination of the velocity of the' iluid and consequently the same may be procured -with equally as great accuracy as where ideal conditions exist.

In the form of'the invention shown in Fi'g. 1, two units are employed instead of a single unit as shown in Fig- 11 and theunits are connected together. Also in this form of the invention, adiustment is had by simultaneously lengthening one branch of the tube structure and shortening the other instead of procuring the entire adjustment of one branch only. The particular construction by means of\.which this is accomplished will now be described in detail. It is again assumedthat the meter is installed in the pipe I0.

In this form of the invention, four vibration transmitters |43, |44, |45, and |46, are employed which are situated at locations designated as stations E, F, G. and H. A11 of these vibration transmitters are the same as the transmitters and I2V and the same reference.V charactershave been used for the corresponding parts of all of them. The two vibration transmitters |43 and |44 are connected together through a tube structure |24, shown in detail in Figs. `1 and 3. The fittings 'I6 `of'these vibration transmitters are connected to bent tubes |25 and |26, which are connected to suitable valves |21 and |28. The

valves |21 and 28 are vconnected to a straight' tube |29, which extends parallel to the rpipe I0 and which is formed with a slot or opening |30, slightly to one side of the' middle ofthe tube structure. In like manner, the two vibration transmitters |45 and |48 are connected through fittings 16 thereof, to bent tubes |3| and |32 forming part of a'tube structure |41 which tubes in turn are connected to valves |33 and |34. Valves |33 and |34 have connected to them a straight tube |35, similar to the tube |29, and parallel therewith, which tub has formed in it a slot, the same being situated to one side of 55 the middle of the tube structure the same as the slot |30 of the tube structure |24. Slidably mounted on the tubes |29 and |35 are two sleeves |36 and |31 which cover the slots |30. These sleeves have secured to them, two bent tubes |30 and |39, which are secured -to valves |40 and 14|. The valves |40 and |4| have secured to them a straight tube |42 extending parallel with the tubes |29 and |35 and the pipe I0, which tube, as Ishown in Figs 2 is formed with a slot 343 similar to the slots |30'of tubes |29 and |35. The tubes |38, |39, and |42 form another tube structureI which I have indicated in its entirety at |48. The tubes |38,- |39 and |42 are in communication with the sleeves |36 and |31 and by means of the slots |30 are further in communication with the tubes |29, |25, |25 and the vibration transmitters |43 and |44, and likewise the vibration `transmitters |45 and |46. As the tube structure |48 including two sleeves |36 and |48 relative to the tube structures |24 and |41, a device is employed which is illustrated in detail in Fig. 3. An arm |49 isy employed which is 10 formed atene end with a clamp |50 by means of which the same may be V'rigidly attached to tube |29 of the tube structure |24. Between 4the ends of this arm there is provided a guideway |5| along which the tube |38 isslidable. A second arm |52 is likewise attached to the tube |38 1 through a clamp |53. This'clamp is threaded at one end to receive a screw |54 which passes,-,

nected through conductors |81 and |88 with the through the outer end of the arm |49 and which", I

.secondary |89; of a transformerv |90.

is rotatably mounted therein. This screw hasv attached to it collars |55 and |56 by means of which said screw is deprived of longitudinal movement relative tofarm |49. The screw |54 may be rotated by means of a knurled head |51. Tube structure |48`is also slidable relative to the sitionedl toward one side of the middle of said f tube structure. A sleeve |59-surrounds this tube and is slidable thereon, said sleeve serving to cover the slotor opening 343; Sleeve V|59 has atl tached to it another tube |60 which is similar to the tube 1| of thej'for'mpf the invention shown 1= in Fig. 11'and whichio'rfthe sake of convenience will hereinafter be referredto as tube structure 4Q |63. The tube |601is infrcommunication withtube |42 through slot343andfhas attached toit a- Vibrationv producing', deyic 4|82 identical wit the vibration producingffdeviee device being identical! with that previously described, thesame hasnotfbeenillustrated in de- The tube structureflftmay':be moved alongthe tube |42 through'an radjusting device shownin detailin Fig. 2 and sim'ilar'to that illustrated in Fig. 3. -This device comprises anarm |64 which is V formed with a clamp |85-'by means of which said arm mayl bel rigidly lattached tothe tube |42.` The arm |64 is th'readed'as indicated at |98 to receive a threaded-.adjustingscrew |611;

This screw is rotatably mountedfinlan'other arm.;V

|68 Which'is rigidly attached t()thefsleve |59 through aclamp |69. The screw '|61lhas at#v tached to it twovcollars- |10 and |1| which de-f prive' the vvsame' of longitudinalv movement with respectto the arm |68. VAs'thefscrewl|81 is rotatoo through a knuried hadm the-tube struc-1' ture fea-1s shifted' aiongthetube du;

Y, For the purpose of measuring the movementoi the tube structurel with respect to` thetube structures v|24v and. |41 and tonmeasuringv,the movement of the tube structure |63 with respect 7o tothe tube-M42, ascale is employed which isinf dicatedl at |13 in Figs. \-i and 2. 'This lscaleis at- Ytached at one` end to thelaijmwl througha bracket |14 and.is' 'attached\ at 'its other .end

through bracket |15 totube' |42. The-bracket l K I4 previously-y,A referred-to. :The methodot attachment of the.r 5 tube |60vto the vibration'producing device |821" and the construction of thevibration producing" the same may be secured to said tube while screws |11 and |18 serve to hold the scale secured to said brackets. The brackets |14 and |15 are so disposed that the scale |13 lies between the pipe |0 and the tube |42. The scale |13 has two sets of graduations on the same indicated at |19 and |80. An arm'IBl rigidly secured to sleeve |59 is adapted toride along the scale |13 and is formedwith apoi'nter |82, movable along theI graduations |80. A similar arm |83 attached to the pipe |0 is provided with a pointer |84 adaptlo ed to move relative to the graduatons |19. The arm |83 is formed with a band |85 adapted to encircle the pipe I0, which band is constructed with a .clamp |86 by means of which the same may be rigidly secured' to the pipe. 15

The vibration producing device |62 is con- .4 l The primary |9|` ci'. this transformer is )connected- Thisfgenerator includes |96 and |91 'in identicallyqthe same mannenfas' the generator20 and-,battery 6,3 of the formfof the inventionfpreviously referred to. These parts having been"previously described, will not be@y again described in reference to this form ofthe?A invention.

d At stations rj and J in the pipe lo which oorre- 3 spond to thestatio'lnsCA and D of said pipe in `the form of the iinvent'ioxif:shown in Fig. 11 are situated two vibrationfdetectors |99 and 200. These detectors are :identical with the detectors 2| and 22 and have connected to` them electric pickup. devices 28| and 202 identical with the pickup def vices 25 and 26. By means of a selector 203 identical with selector 3| and circuits 204, 205 and 208 connectedftherewith, thejpickup devices may be connected toan amplifier 201,1 identical with 40 *the ampliiier 3,4. This ampliergincludes a head.`

phone 208 which is connected tofthe amplifier through a circuit 209, whichfheadphone is iden#V tical with the head phone-31. I, f The method of using thedevice-shown in Fig. 4,'5

1 is quite similar to that described in conjunc` tion with the device shown in Fig. 11. The fluid in pipe I0 is first brought to rest and theI tube -structures |49 and |63 adjusted until sound heard in the earphone 208v is a minimum when-.50

. the selector 203 is connected-to either ofthe electric ,pickup devices 20| or 202.

"|13 is'then adjusted by loosening clamps |16;`

The scale,l

65; and 169, until the pointer |82 is 'opposite the w f -hoi'dmgarm |83 attaohedtothe pipeA fonsalso 4.loosened by releasing clamp|88 and poirite,` |84 caused to lie opposite the zero markfof graduation; I|19. The various clamps may then all be tightened and thev apparatus isready for use. Theiiuid whose velocity is tozbe measured is ,then caused to nownom rightto'v left! through the pipe |0ai`d selector 203 operated to connect the pickup device 20|-with the amplifier 201.` Tubestructure |48 is now shifted by means of 65 theradjusting screw |54 until the sound 'perceptible 'in the headphone 208 isa minimum. Selector 2031's then 'operated to connect .the electric pickup device 202 with ampliiier` 201 and the tubestructure |63'adjustedwith Yrespect to 70 tube Y. |42untilthe sound :heard is a minimum. Adjustment oftube structure |63.may disturb the'.` adjustment `of tube "structure -|48 and re- |15 is formed with aclamp I'Iiby means of which 17 adjustment ofy the same may, therefore. been ,u

ithroughoonduotors |92 and |93 with an e1eotno ,20g .v

' .f generator |94=identical `with'. the generator 20` i previously referred to. a battery connected to it through conductors j er'mark of the'fgraduation |80'. Theband|95 5,5,

necessary. In such case, the selector 203 is re. versed and the procedure repeated. The adjustment through the two screws |61 and |54 continues until the sound heard in the head phones from both stations I or J is a minimum. Sound intensity adjustments are made as previously described by means of valves |21, |28,

|33, |34, |4|, |40. After such condition has been found, readings are taken'of the movement of the pointers with respect to graduations |19 and |80. These readings together with the value of the frequency of the generator |94 .are used to determine the velocity of flow. It will readily be understood, however, that if desired the scales |19 and |80 .may be marked to read directly in terms of velocity of flow, thereby eliminating the necessity of computation.

The theory of operation of the invention shown in Fig. 1 is the same as that illustrated in Fig. 11. However, with the form of the invention shown in Fig. 1, `reflection of vibrations which would otherwise be caused by irregularities, bends, or other obstructions in the pipe are eliminated. This is effected in the following manner. Referring to Fig. 1 and assuming the fluid to be in motion from right to left as indicated by the arrow, tube structure |48, including slides |36 and |31, is moved by turning hand wheel |51, with selector 203 connected to electric pickup device 20|, until the observer listening to the sound emanating from head phone 208 observes a minimum sound. It will be understood from the explanation of the operation of the simplified form of the device previously given that the operation of sliding tube structure |48 and slides |35, |31 has the effect of simultaneously adjusting the sound to a still lower level in the sam'fmanner as'was done in the simplified form 012r the; apparatus It is clear from the explanationfbf ythe 'sini fied device that the adjustment describedis not suiiicient to insure that vibrations emanatingL ator |62 to vibration transmitters |43 andi4'5 and ifi such manner that vibrations `emanating' 'fronrsaid transmitters combined Vin a f .resultant minimum vibrationat listening station J. It will' be observed that the same adjustment is simultaneously made forvibration transmitters |44 and |46 so that the vibrations from these two transmitters propagated from left to right combine at listening station J to form a minimum. Valves |40 and |4| may be adjusted to regulate the intensity of the vibrations so as to effect a more nearly complete destructive interference at J.

It wm be understood that since the adjust` nini'um" sound y .ductorsf233 and 234 to branch conductors 235 andf231f-238. A phase shifter 239 is ',:nectedto conductors 235 and 236 and is fur- .s'tructure |48 and thereby altering the ng-ths of the sound paths from vibraments have been made so as to eliminate vibrations propagated from left to right past station I, that there will be no vibrations propagated due to irregularities in pipe |0 which may exist outside of the region included between I and J, 5 and which irregularities would otherw'se result in vibrations being reflected at such places returning to the meter proper and interfering with the proper adjustment thereof.

Instead of producing destructive interference Abetween the vibrations emanating from the various stations in the pipe I0 .by adj ting the relative lengths of theA paths from t e sound generator to the various stations, the same may be accomplished by changing thetphase relation of the various vibrations electrically instead of by performing the same result mechanically. A

. structures are dispensed with and a separate vibration producing device employed for each of the vibration transmitters |43, |44, |45, and |46,- whch are designated by reference numerals 226, 221, 228, and 229. The vibration detectors, amplifier, and the. generator of the vibrations are identical in this form of the invention and the same `\reference characters have been used to designate the like parts in the two forms of the invention. In the deviceshown in Fig. 9, the conductors |81 and |88 are connected to two phase Shifters 2H and 2 I2 through branch circuits \\2|3, 2|4 and 2| 5-2| 6. The phase shifter, 2|2`ls in turn connected through conductors 2|1'and 2| 8 with branch conductors 35 ZIB-220 and also branch conductors 22l-222.

The conductors 2|9 and 220 are connected to `other yphase shifter 223 which in turn is connectedtl'irough conductors 224 and 225 with the vibration producing device 228. The conductors 40 22.1222 are A`connected to phase shifter 230 whichis connected through conductors 23| and 232; with the (vibration producing device. 229. h'efiphaselshifter 2|| is connected through conconther c onnected through conductors 240 and 24| with-the vibration producing device 226. In exactly ,the same manner a phase shifter 242 is connected to conductors 231 and 238 and is further connected through conductors 243 and 244 with the vibration producingv device 221.,

The phase shifting devices 2li, 2|2, 223, 230, 239, and 242 may be of any desired type, such '55 as is now well known in the art. lOne such device is shown in Fig. 10, which, however, is merely illustrative. This device is shown as illustrating the phaseshifter 2|| and shows the 'conductors 2|3 vand 2|4 entering `thesarne and 60 the conductors 233-and 234 leaving said phase shifter. The phase shifter 2|| constitutes a number of units, three being shown in the particular device illustrated and indicated at 245, 246, and 241. These units are identical in construction, excepting as to the relative values of the various elements thereof and for this reason only unit 245A will be described in detail. This unit consists of two variable condensers 248 and 249 and two inductances 250 and 25| which may 70 be' of fixed value or adjustable as desired. 'Ihe condenser 24,8 is connected through conductors 252 and 253 to the two inductances 250 and 25| respectively. These inductances are in turn connected in inverse "relation to the condenser` 249 through conductors 254 and 255. The condenser 248 is connected through' conductors 255 and 251 with two of the poles of a double pole double throw switch 258. The other two poles of this switch are shorted through a conductor 259 while the blades of the switch are connected to a buss 260 which in turn is connected to the conductors 2l4 and 233. Condenser 249 is likewise connectedl through conductors 26| and 262 with two of the poles of a double pole double throw switch 263. The other poles of this switch are shorted through a conductor 264 and the blades of this switch are connected to a buss 266 inthe same manner as the other switch, whichbuss is in turn connected to the conductors I234 and 2i3. Each of the units 245, 246 and 241 are likewise connected to the busses 260 and 265 so that the said units may be connected in series with one another and in the required circuit. The various units operate 1n a well known manner to change the phase of the current leaving the same without changing the frequency or the magnitude of the current. The change in phase can be effected by cutting in units and the variation procurable depends upon the number of units employed in each phase shifter. When it is desired to cut in one of the phase shifters the switches 258 and 263 are thrown to connect the blades thereof with the respective unit. When not desired, the blades are shifted in the opposite direction to connect the' conductors 259 and 264 across the gaps in the busses 260 and 265. Phase changes may also be obtained in a continuous manner and not in steps as described by employing continuously variable condenser and inductance elements well known to the art.

In the use of the invention shown-in Fig. 9 it is merely necessary to go through the same procedure as in the form of the invention shown in Fig. 1. In this connection, however, the adjustments are made by manipulating the phase Shifters 223 and 238, these shifters being similarly adjusted and the phase shifters 242 and 230 being likewise similarly adjusted so. as to produce minimum sound at station I. Similarly phase Shiftersl 2H and 2I2 are adjusted to produce minimum sound intensity at station J. After the adjustments have been made the velocity of the uid can be determined. It will be understood from the explanation prevously made in connection with Fig. 11 that the alteration in the length of tube structure I3 produced no other result on the sound waves within pipe I0 than altering the phase of the sound emanating from source l2. This alteration in phase can be determined from the alteration in the length-of tube structure I3. For the case now considered, the alteration in phase is indicated'directly by the phase Shifters. The calculation of the fluid velocity is then identical with that previously described.

Changes in the specific form-of my invention,

Yeas herein disclosed, may be made within the scope of what is claimed without departing from the spirit of my invention.

Having described my invention, what I claim as new and desire to protect by Letters Patent is:

1. The method of determining the rate of flow phase of the vibration at the other locality to produce a detrminable effect upon the resultant of the vibrations and in ascertaining the rate of flow of the uid from the changes of relative phase of the vibrations in the fluid. 5 2. A fluid meter comprising means for set-' ting up mechanical vibrations of definite frequency, means for transmitting such vibrations -to the uid at two localities along the course of travel thereof and over different paths, means 1g for transmitting lthe vibrations to the fluid at two other localities-in the iluid and over other differing paths, and means for adjusting the various paths of the vibrations to procure destructive interference between the vibrations of 15 the firstgroup and those of the second group.

3. The method of determining the rate of flow of iiuids which consists in producing mechanical vibrations of definite determinable frequency, in transmitting the vibrations to the uid at 20 two localities while the fluid is at a known state of motion, in changing the phase relation betweenthe vibrations at the two localities while the fluid is at the state of motion to be, determined to procure predetermined conditions of 25 the vibrations in the fluid and in ascertaining the rate of flow of the fluid from the change in phase of the vibrations at the two localities.

4. A fluid meter comprising means for setting up mechanical vibrations of definite frequency, 30 two vibration transmitters adapted to transmit the vibrations to the fluid whose rate of flow is to be measured, conduits connecting said means with both of the vibration transmitters and having a.r iluid therein through which the vibrations 35 may be propagated and means for adjusting the relative length4 of the conduits to procure a change in phase relation between the vibrations at the two transmitters.

5. A fluid meter comprising means for setting 4o up mechanical vibrations of denite frequency, two vibration transmitters adapted to transmit the vibrations to the fluid whose rate of flow is to .be measured, conduits connecting said transmitters together, means for adjusting the relative 45 length of said conduits, two other vibration transmitters adapted to transmit the vibrations to the fluid whose rate of flow is to be measured, conduits connecting said second transmitters together, means for adjusting the relative length 50 of said second named conduits, conduits connecting the rst named conduits and the second named conduits together and to said means for setting up vibrations and means for adjusting the relative length of said last named conduits. 6. The method of determining the rate of flow of fluids which consists in producingmechanical vibrations of definite determinable frequency, in transmitting the vibrations to the fluid while the fluid is at a. known state of motion and at two known localities in the fluid such as to cause a resultant vibration at a certain station in the fluid', in further setting up vibrations of definite determinable frequency, in transmitting such vibrations to the fluid while the fluid is flowing with the velocity which is to be determined and at two known localities in the fluid such as to cause a resultant vibration at a certain station in the iiuid, in varying the phase of the vibrations at one ofthe last named localities of introduction into' the fluid to produce a resultant vibration at the last named station which will be definitely related to the resultant vibration first referred to, and in ascertaining the rate of flow of the fluid from the 'relation between the phases-of lthe vibrations in both instances.

' 7. In a uid meter, a conduit, detecting devices at two spaced stations in the conduit, means for setting up mechanical vibrations of definite frequency, means for transmitting such vibrations to the fluid intermediate such stations at a plurality of localities, means for adjusting the phase of the vibrations at such localities to limit the vibrations to the region between said stations.

8. .The method of determining the rate of flow of fluids which consists in transmitting mechanical vibrations of definite determinable frequency to the iluid at two localities, in adjustingthe paths of the vibrations to procure destructive interference of the vibrations in one direction, in transmittingnechanical vibrations of definite determinable frequency to the uid at two other localities, in adjusting the paths of said vibrations to procure destructive interference of the vibrations in one direction, in further adjusting the paths of the vibrations to procure destructive interference between the rst named vibrations and the second named vibrations and in ascertaining the rate of flow of the fluid from therelative lengths of the paths.

9. The method of determining the rate of flow of fiuids which consists in producing mechanical vibrations of definite determinable frequency, in transmitting the vibrations to the uid at two localities, while the fluid is at rest, in adjusting the phase relation between` the vibrations to procure destructive interference, in transmitting vibrations of the same frequency to the uidat the ascertaining the rate of flow of the fluid from the change in phase relation of the vibrations.

10. A fluid meter comprising a conduit through which the fluid passes, a device for settingup mechanical vibrations of definite frequency, two vibration transmitters positioned in said conduit at spaced localities, tubes connecting said device with said transmitters, means for adjusting the relative lengths of said tubes to vary the phase relation of the vibrations emanating Vfrom said transmitters, and a detector responsive to vibrations in the uid.

11. A uid meter comprising a conduit through which the iiuid passes, two vibration transmitters positioned in said conduit at spaced localities, means for setting up mechanical. vibrations of definite frequency in one of said transmitters,v

means for setting up mechanical vibrations of the same frequency in the other of said transmitters, means for varying the phase relation between said vibrations at the transmitters and a detector responsive to vibrations in the fluid.

l2. Anapparatus for determining the rate of iiow of uids which comprises a conduit for the fluid whose rate of ow is to be measured, means for setting up mechanical vibrations of the same frequency in the moving fluid at a plurality of localities along the conduit, means for adjusting the phase of the vibrations at one locality with respect to the phase of the vibrations at another 1ocality to produce a determinable eiTect upon the resultant of the vibrations, means responsive to said vibrations for determining said resultant, and means for measuring the degree of adjustment of said adjusting means.

13. In a fluid meter, means for transmitting mechanical vibrations of definite determinable frequency to the fluid at two localities along the -course of travel thereof, means for adjusting the .paths of the vibrations to procure destructive interference of the vibrations in one direction, ymeans ,fortransmitting mechanical vibrations of :definite determinable frequency to the iluid at two 5 the iluid whose velocity is to be measured travels,

'vibration detectors in said conduit at spaced localities, means for transmitting vibrations of definite frequency to the fluid in said conduit at a 'plurality of spaced localities within said conduit, and between said vibration detectors, andmeans for adjusting the relative phase of the vibrations to procure` determinable effects upon said vibration detectors.

15. In a `fluid meter, a conduit through which 25 the uid whose velocity is to be measured travels,

vibration detectors in said conduit at spaced lou calitles, means for transmitting vibrations of deflnite frequency to the iluid in said conduit at two .spaced localities within said conduit and between 30 "said vibration detectors, and means for adjusting the relative phase of the vibrations to procure de'- terminable effects upon said vibration detectors.

16. In a iiuid meter, a conduit through which the fluid whose velocity is to be measured travels, 35 vibration detectors in said conduit at spaced localities, means for transmitting vibrations of definite frequency to the fluid in said conduit at four spaced localities within said conduit and between said vibration detectors, means for ad- 40 justing the relative phase of the vibrations at two localities to procure a determinable effect' upon one of said vibration detectors, and means for adjusting the relative phase of the vibrations at the other two localities to produce-a determinable 45 up mechanical vibrations of definite frequency,

means for transmitting the vibrations to the 0 uid over two paths independently of the uid at two localities alongy the course of travel thereof to produce vibrations of the same frequency at such localities acting simultaneously at the same region of the uid to produce a determinable effect, means for varying the length of one of said paths to vary the resultant effect of the vibrations on the fluid, and vibrationdetectors for determining the resultant effects of said vibrations.

19. A iluid meter comprising means for setting '70 up mechanical vibrations of denite frequency, two vibration transmitters adapted to transmit the vibrations to the fluid whose rate of flow is to be measured, conduits connecting said means with both of the vibration transmitters and hav- 75V,y

ing a iiuid therein through which the vibrations may be propagated and means calibrated in terms proportional to ow for adjusting the relaltive length of the conduits to procure a change in phase relation between the vibrations at the two transmitters and two vibration detectors for determining the resultant effects of said vibrations.

20. In a uid meter, a conduit for the uid whose rate of iiow is to be measured, means for setting up mechanical vibrations of a certain frequency, a tube connected to said means, branch tubes connected to said tube and to said conduit at spaced localities within said conduit, vibration transmitters withinlsaid conduit connected to said branch tubes, means for adjusting the relative lengths of said branch tubes, and

I vibration detecting means within said conduit.

21. In a uid meter, a conduit for the uid whose rate of iiow is to be measured, means for setting up mechanical vibrations of a certain frequency, a tube connected to said means, a` tube structure connected to said tube and including branch tubes communicating with said conduit at spaced localities, a second tube structure connected to said tube and including branch tubes connected to said conduit at other spaced localities, vibration transmitters Within said conduit connected to said branch tubes, means for adjusting the relative lengths of the branch tubes of said irst named tube structure, means for independently adjusting the relative lengths of the branch tubes of said second named tube structure, and vibration detecting means within said conduit.

22. In a iuid meter, a conduit for the fluid whose rate of flow is to be measured, means for setting up mechanical vibrationsl of a certain frequency, a tube connected to said means, branch tubes connected to said tube and to said. conduit at spaced localities within said conduit, vibration transmitters within said conduit connected to said branch tubes, means for adjusting the relative lengths of said branch tubes, and two spaced vibration detectors within said conduit between which said vibration transmitters are situated.

23. In a iluid meter, a conduit for the uid whose rate of flow is to be measured, means for setting up mechanical vibrations of a certain frequency, a tube connected to said means, a tube structure connected to said tube and including branch tubes communicating with said conduit at spaced localities, a second tube structure connected to said tube and including branch tubes connected to said conduit at other spaced localities, vibration transmitters Within said conduit connected to said branch tubes, means for adjusting the relative lengths of the branch tubes of said first named tube structure, means for independently adjusting the relative lengths of the branch tubes of said second named" tube structure, and two spaced vibration detectors disposed Within said conduit and between which all of said vibration transmitters are situated.

HENRY E. HARTIG. 

